Semiconductor nanowire structures possess beneficial characteristics suitable for numerous applications. Vertically extending nanowire structures of III-V compound semiconductor materials are of particular interest owing to their high electron mobility and direct band gap properties. However, conventional nanowire fabrication schemes often call for the use of semiconductor substrates of non-standard crystal orientations to resolve issues arising from orientation-dependency of the nanowire growth direction. The use of non-standard substrates generally increases costs. Moreover, the need for metal particles as catalysts in the conventional fabrication methods makes them less compatible with certain applications, such as complementary metal-oxide-semiconductor (CMOS) manufacturing.